Chapter 21: Allergic and Anaphylactic Reactions Flashcards
allergic reaction
hypersensitivity reaction resulting from exposure to an allergen which can occur at any time and to anyone
pruritus
mild localized reaction presenting as redness, itchy skin
urticaria
edema or a mild systemic reaction resulting in widespread hives
anaphylactic reaction/anaphylaxis
a systemic, multi-system, life-threatening condition with respiratory failure, circulatory collapse, and shock, associated with severe swelling of the upper and lower airways, constriction of the bronchioles, leakage of fluid from the capillaries, systemic vessel dilation, and an increased mucous production
immune system
defense mechanism of the body to fight off invasion by foreign substances
antigen
foreign substance
allergen
specific tyoe of antigen
immune response
immune system detects the antigen and produces antibodies
antibodies
proteins that search for the antigen, combine with it, help to destroy it
anaphylactic shock
cardiovascular collapse and hypotension with a life threatening response to an allergen
IgE-mediated anaphylactic reaction
aka an anaphylactic reaction
hypersensitivity
after the body is first exposed to an antigen, an anaphylactic reaction can occur when the person is exposed agian
sensitization
developing hypersensitivity on the first exposure to an antigen
histamine
primary chemical mediator released from mast cells and basophils, causes vasodilation, bronchoconstriction, and an increase in capillary permeability
anaphylactoid reaction
when chemical mediators are released from the mast cells and basophils the first time the antigen is introduced into the body without the patient ever being sensitized
non-IgE-mediated reaction
an anaphylactoid reaction
ways an antigen can enter the body
- injection
- ingestion
- inhalation
- contact (absorption)
most common method of antigens getting into body associated with anaphylactic reaction
injection
hymenoptera
the majority of severe allergic reactions and anaphylaxis related to insect bites. bees, vespids (wasps etc), stinging ants
venom
from insect bites or stings, most often cause localized reaction
foods
can cause reactions in some people
pollen
can cause reactions in some people
medications
known to cause reactions in some patients
many other substances
can produce anaphylactic reactions
exercise
can accentuate the anaphylactic response
weather conditions
can trigger an anaphylactic response
latex
most often found in exam gloves and other medical devices
malaise
a generalized feeling of weakness/discomfort
endotracheal intubation
placement of a tube in the trachea to facilitate breathing
hives
urticaria, raised red blotches all over skin
rhinitis
stuffy, runny, itchy nose
two key categories of signs and symptoms that specifically indicate a severe anaphylactic reaction, patient needs epinephrine
- airway and respiratory compromise: airway occlusion, respiratory distress or respiratory failure with possible wheezing or stridor
- shock (hypoperfusion): absent or weak pulses, tachycardia, decreased BP, deteriorating mental status
emergency medical care for anaphylactic reaction
- maintain a patent airway
- suction any secretions
- maintain adequate oxygenation
- be prepared to assist ventilation
- administer epinephrine
- consider calling ALS
- initiate early transport
indicators of a severe systemic anaphylactic reaction
acute onset with involvement of skin, mucosal tissue, or baoth (hives, itching, flushing, redness, edema to face, lips, tongue)
AND
signs or symptoms of respiratory distress
AND/OR
signs or symptoms of poor perfusion or hypotension
biphasic anaphylactic reaction
late stage reaction that occurs when the initial signs and symptoms resolve, can be life threatening, treated the same as an initial anaphylactic reaction
epinephrine
drug of choice for emergency treatment of a systemic allergic reaction, mimics sympathetic nervous system, has alpha 1 (causes vessel constriction), alpha 2 (regulates amount of vasoconstriction), beta 1 (increases HR, force of contraction of heart, and speed at which electrical impulses are carried to heart), beta 2 (causes bronchiole smooth muscles to dilate) properties
auto-injector
spring activated, concealed needle that is designed to deliver a precise dose of epinephrine when activated
